From Generation to Generation:The Genetics of Jewish Populations Noah A. Rosenberg and Steven P. Weitzman Keywords Ashkenazi Jews, Cohen Modal Haplotype, Population Genetics, Samaritans, Y Chromosome The year 2014 marks the 35th anniversary of two noteworthy papers, one in this journal and the other in the American Journal of Human Genetics, posing the same famous question: are the different Jewish populations from around Europe, the Middle East, and North Africa more genetically similar to each other, or are they more similar to the local non-Jewish populations in the regions where they were historically located? Both studies gathered blood group and protein variation data from a variety of Jewish and non-Jewish populations, compiling significant "classical marker" data sets commensurate with the standard for human population genetic studies at the time. Writing in the American Journal of Human Genetics, Karlin et al. (1979) reported, "We found the Ashkenazi, Sephardi, and Iraqi Jewish populations to be consistently close in genetic constitution and distant from all the other populations," concluding that, in fact, the Jewish populations were generally more genetically similar to each other. In Human Biology, Carmelli and Cavalli-Sforza (1979) wrote, "A wide scatter of the Jews was observed among clusters of non-Jews," finding that, on the contrary, the Jewish groups were largely more similar to the local non-Jewish populations. While these studies used some of the best statistics and data available at the time, they highlight the dramatic changes that have taken place in human population genetics research over the last 35 years. The field has proceeded through a succession of new types of genetic markers, the size of classical data sets has been spectacularly superseded, and the effort to understand new and larger collections of markers has provided many novel methods for the statistical toolbox of population genetics. Further, it has become clear that levels of similarity in human populations are sufficient that the resolution of population relationships among closely related groups often requires both an amount of data and a computational capacity that would have been unimaginable to researchers working in 1979. [End Page 817] What has not changed, however, is the interest in questions about the genetics of Jewish populations—in fact, it has intensified. From the viewpoint of population genetics, the history of the various Jewish populations provides a scenario capable of inspiring and testing new population genetic methods, a rare case in which multiple groups with a component of shared identity and descent have lived over a large geographic range for a long period of time in a region of the world with a deep written record. From the viewpoint of scholarly fields that treat Jewish culture and history as the object of investigation, the use of genetics as an approach for understanding Jewish populations and their history taps into an intrinsic Jewish cultural interest in origins and migrations, a recognition of nonidentical but overlapping senses of Jewish group membership—from cultural to religious to genealogical—and the centrality to Jewish culture of the inheritance of Jewishness within families, as reflected in the title phrase, "from generation to generation." Seeking to advance and understand trends in the genetics of Jewish populations, this special issue focuses on Jewish population genetics, setting new developments in relation not only to past population genetic studies but also in the broader context of Jewish studies scholarship. The special issue builds upon a course of the same name that we held jointly in the biology and Jewish studies programs at Stanford University in the autumn of 2012, featuring the issue’s contributors as guest lecturers. Human population genetics is, in part, a form of historical endeavor, potentially illuminating the effects of social practices such as endogamy and conversion, the history of population relationships, and the magnitude, direction, and timing of migration events. At the same time, the field can be viewed as historically situated, with its underlying assumptions, its expression in language, and its cultural reverberations and social implications subject to research in their own right. As a collection of articles spanning multiple forms of inquiry, this special issue aims to both present and contextualize current research, discussing its cultural environment and the challenges that lie ahead...
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